Trailing-Edge
-
PDP-10 Archives
-
BB-L289B-RK
-
data.rno
There is 1 other file named data.rno in the archive. Click here to see a list.
.autoparagraph.flag capital.nofill
.right margin 68
+---------------+
! d i g i t a l ! I N T E R O F F I C E M E M O R A N D U M
+---------------+
.s
Date: 20-January-82
From: TSG/NCSS
Loc: MR1-2/H22
Ext: HOTLINE 5911
.skip
.skip
Subj: Use of a Datascope
.subtitle Subj: Use of a Datascope
.fill
.s
The Spectron Datascope is a monitoring device which can display
all the data transmitted and received over a physical line. It is
hooked into the line between the modem and the physical line
driver. It can be used for diagnosing communications problems
over a wide range of protocols, devices, and speeds.
.s
The Datascope is about the size of a small oscilloscope. The
characters on the line are displayed on a small screen. There are
lots of controls for setting the byte size of the characters, the
way in which the bits are to be interpreted, and how the display
is to be formatted.
.s
Some models of the Datascope can be programmed to do things like
search for certain character patterns and stop the display and so
on. Some can be used with a tape unit which can record the line
activity for analysis later.
.s
The Datascope is the best tool we know of for determining exactly
what is happening on a communications line. Unfortunately, it is
very expensive, costing many thousands of dollars. For this
reason, individual offices almost never have a Datascope of their
own. Nonetheless, if you will be doing a network installation or
will be otherwise involved in potentially difficult network
problems, it is a good idea just to inquire into the availability
of a Datascope in case the need for one should arise. Some
districts or regions own one Datascope which can be loaned out to
its local offices. If you are lucky and are involved with a rich
customer, the site may have one of its own.
If there is no way you can get your hands onto a Datascope, a
breakout box, which costs only a few dollars, may also be
helpful. This can at least tell you what is happening with the
EIA modem signals and whether data is being sent or
received.
.s
The Spectron people offer a course on the use of the Datascope. A
quicker way to learn its use is to simply find someone who knows
how to use it and to ask him or her to show you how it works. The
controls are simple and an hour or two of hands-on time should be
plenty. The remainder of this memo describes how to use the
Datascope.
.hl 1 HOOKING UP THE DATASCOPE
.s
The Datascope is hooked into the line between the line driver
and the modem. Plug the EIA connector coming out of
the interface for that line into the back of the
Datascope in the position marked "Bus Mach/RCU". Then patch a
plug between the "modem" connector on the Datascope and the modem.
Then power on the Datascope. Note that the datascope need not be
on for the link to work.
.hl 1 LIGHTS
.s
The row of lights across the display corresponds to the EIA-CCITT
modem-terminal interface. For example, if light 8 is on, it
indicates that Carrier Detect, pin 8, is high. This display is
the same as the display in a breakout box. A listing of the pin
numbers is included later on in this memo.
.hl 1 DATASCOPE SWITCH SETTINGS
.s
To look at an asynchronous data stream set the switches on the front
panel of the data scope as follows:
.nofill.nojustify
.s
Switches:
.s
Name Setting
.s
2 char/normal N/A
Internal/modem Internal
Manual N/A
1-8/8-1 8-1 normal order, bit 1 arrives
first
Send Down - normal polarity
Rcv Down - normal polarity
Both Down - normal polarity
.s
.s
Dials:
.s
Send/Rcv FDX - Display send/receive on
alternate lines (2
lines/timeframe).
Ideal for full-duplex.
.s
Framing ASYNC 8 - Clock 8 bit data bytes
(the bit count includes
the parity bit).
.s
Code A - ASCII is displayed.
.s
Marker FDX - Received data black on white
when CD high (pin 8)
Send data black on white
when RTS high (pin 4)
.s
Suppress OFF - Shows all activity on the
line in both directions.
Time relationships can
be seen.
.s
.s
Thumb-wheels
.s
Speed Set to terminal baud rate per speed
table below.
.s
.s
SPEED TABLE
.s
A - 50 E - 150 I - 1200 M - 3600
B - 74.2 F - 300 J - 1800 N - 4800
C - 110 G - 600 K - 2000 O - 7200
D - 134.5 H - 1050 L - 2400 P - 9600
.s
.s
Framing pattern N/A
.s
Sync reset N/A
.s
Rocker switches
.s
Display Run
Prog Idle
.s
.fill.justify
.hl 1 HEX-ASCII DATA CONVERSION
.s
The following chart can be used to convert 8-bit ASCII to HEX. It
can also be used to obtain the binary for each HEX digit. To
convert from HEX to ASCII, choose the first HEX digit from the top
and the second HEX digit from the left, and then look where the
row and column meet. To convert from ASCII to HEX, choose the
second HEX digit from the row in which the character appears and
the first HEX digit from the column. The reason there are two
choices for the first HEX digit is because parity may be odd,
even, or non-existent. For no parity, choose B8=0. For even or
odd parity, choose either B8=0 or B8=1, whichever one will give
you the right number of 1 bits.
.page
For example,
.nojustify.nofill
.literal
ASCII "L" = 4C (no parity)
= CC (even parity)
= 4C (odd parity)
|------------------------------------------------|
| B7----------->|0 |0 |0 |0 |1 |1 |1 |1 |
| B6-------->| 0 | 0 | 1 | 1 | 0 | 0 | 1 | 1 |
| B5----->| 0| 1| 0| 1| 0| 1| 0| 1|
|---------------\ | | | | | | | |
| 1st HEX B8=0 \ | | | | | | | |
| Digit ----\ ---|---|---|---|---|---|---|---|
| B8=1 \ 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|--------------\ ---|---|---|---|---|---|---|---|
| 2nd HEX Digit \ 8 | 9 | A | B | C | D | E | F |
|----------- ||---|---|---|---|---|---|---|---|
|B4|B3|B2|B1| || | | | | | | | |
|--|--|--|--|---||===|===|===|===|===|===|===|===|
| 0 0 0 0| 0 ||NU |DL | | 0 | @ | P | ` | p |
|-----------|---||---|---|---|---|---|---|---|---|
| 0 0 0 1| 1 ||SH |D1 | ! | 1 | A | Q | a | q |
|-----------|---||---|---|---|---|---|---|---|---|
| 0 0 1 0| 2 ||SX |D2 | " | 2 | B | R | b | r |
|-----------|---||---|---|---|---|---|---|---|---|
| 0 0 1 1| 3 ||EX |D3 | # | 3 | C | S | c | s |
|-----------|---||---|---|---|---|---|---|---|---|
| 0 1 0 0| 4 ||ET |D4 | $ | 4 | D | T | d | t |
|-----------|---||---|---|---|---|---|---|---|---|
| 0 1 0 1| 5 ||EQ |NK | % | 5 | E | U | e | u |
|-----------|---||---|---|---|---|---|---|---|---|
| 0 1 1 0| 6 ||AK |SY | & | 6 | F | V | f | v |
|-----------|---||---|---|---|---|---|---|---|---|
| 0 1 1 1| 7 ||BL |EB | ' | 7 | G | W | g | w |
|-----------|---||---|---|---|---|---|---|---|---|
| 1 0 0 0| 8 ||BS |CN | ( | 8 | H | X | h | x |
|-----------|---||---|---|---|---|---|---|---|---|
! 1 0 0 1| 9 ||HT |EM | ) | 9 | I | Y | i | y |
|-----------|---||---|---|---|---|---|---|---|---|
| 1 0 1 0| A ||LF |SB | * | : | J | Z | j | z |
|-----------|---||---|---|---|---|---|---|---|---|
| 1 0 1 1| B ||VT |EC | + | ; | K | [ | k | { |
|-----------|---||---|---|---|---|---|---|---|---|
! 1 1 0 0| C ||FF |FS | , | < | L | \ | l | | |
|-----------|---||---|---|---|---|---|---|---|---|
| 1 1 0 1| D ||CR |GS | - | = | M | ] | m | } |
|-----------|---||---|---|---|---|---|---|---|---|
| 1 1 1 0| E ||SO |RS | . | > | N | ^ | n | ~ |
|-----------|---||---|---|---|---|---|---|---|---|
| 1 1 1 1| F ||SI |US | / | ? | O | _ | o |DT |
|------------------------------------------------|
.end literal
.s
.page
.hl 1 EIA PIN DEFINITIONS
.s
.literal
+----------------------------------------------------------------+
| Pin| Name |To To | Function | Circuit |
| | |DTE DCE| |(CCITT) (EIA) |
|----+------+-------+----------------------------+-------+-------|
| 1 | FG | | Frame Ground | 101 | (AA) |
| 2 | TD | > | Transmitted Data | 103 | (BA) |
| 3 | RD | < | Received Data | 104 | (BB) |
| 4 | RTS | > | Request To Send | 105 | (CA) |
| 5 | CTS | < | Clear To Send | 106 | (CB) |
| 6 | DSR | < | Data Set Ready | 107 | (CC) |
| 7 | SG | | Signal Ground | 102 | (AB) |
| 8 | DCD | < | Data Carrier Detect | 109 | (CF) |
| 9 | | < | Positive DC Test Voltage | | |
| 10 | | < | Negative DC Test Voltage | | |
| 11 | | | Unassigned | | |
| 12 | SDCD | < | Sec. Data Carrier Detect | 122 | (SCF) |
| 13 | SCTS | < | Sec. Clear To Send | 121 | (SCB) |
| 14 | STD | > | Sec. Transmitted Data | 118 | (SBA) |
| 15 | TC | < | Transmitter Clock | 114 | (DB) |
| 16 | SRD | < | Sec. Received Data | 119 | (SBB) |
| 17 | RC | < | Receiver Clock | 115 | (DD) |
| 18 | | > | Receiver Dibit Clock | | |
| 19 | SRTS | > | Sec. Request To Send | 120 | (SCA) |
| 20 | DTR | > | Data Terminal Ready | 108.2| (CD) |
| 21 | SQ | < | Signal Quality detect | 110 | (CG) |
| 22 | RI | < | Ring Indicator | 125 | (CE) |
| 23 | | > | Data Rate Select |111/112|(CH/CI)|
| 24 | (TC) | > | External Transmitter Clock | 113 | (DA) |
| 25 | | > | Busy | | |
+----------------------------------------------------------------+
.end literal
.s